This invention relates to a heat exchanger and, more particularly, to a heat exchanger utilizing a plurality of thermal siphon pipes which contain a heat exchange fluid for removing heat from a hot fluid, such as steam.
In electrical power generation systems, the spent steam from a steam turbine is normally passed to a once-through condenser in which feedwater is passed in a heat exchange relationship with the steam to condense the steam. However, in view of the substantial water consumption and thermal pollution involved, these types of condensers are becoming less and less desirable.
As a result, various types of dry heat exchangers have been suggested which, in their basic form, utilize pressurized air to condense the steam. However, these dry condensers are considerably more expensive than the water condensers discussed above because of the fan power required and the high cost of the heat exchanger portion of the condenser. Also, the dry condensers have poorer cooling potential than the water condensers.
A third form of heat exchanger that is possible in these types of environments is the so-called heat pipe heat exchanger which utilize a plurality of horizontally extending pipes, closed at each end and having a wicking material formed on their interior surface. A heat exchange fluid is disposed in the pipes and is vaporized by the heat of the steam which is passed over a portion of the pipes, and air or the like is passed over the other portions of the pipes to condense the heat exchange fluid. However, these types of arrangements are unpractical in a large system since the wicking material is expensive, the pipes are difficult and costly to manufacture, and the pipes are restricted to use in a horizontal position.